Index of /OOP
OBJECT ORIENTED
PROGRAMMING
D
Day
2:
Dasar Pemrograman Java
TOPIK:
|
|
|
|
|
|
|
|
|
|
|
Menggunakan
M
k komentar
k
t di file
fil sumber.
b
Membedakan antara valid dan invalid identifiers.
Mengetahui
g
Java technology
gy keywords.
y
Mengetahui 8 tipe data primitif.
Mendefinisikan literal value untuk tipe data numerik dan
tekstual.
tekstual
Mendefinisikan primitive dan reference variable.
Mendeklarasikan variabel bertipe
p class.
Membuat obyek dengan menggunakan operator new.
Mengetahui nilai inisialisasi default.
St t t t pada
State-state
d saatt assign
i nilai
il i pada
d variabel
i b l bertipe
b ti
class
Garbage collection
SOURCE FILES
|
|
Java source fil
J
files must end
d with
i h the
h .java
extension.
Th
Three
top-level
t l
l elements
l
t known
k
as compilation
il ti
units may appear in a file.
Package Declaration
y Import Statements
y Class Definitions
y
CLASS FUNDAMENTALS: MAIN METHOD
|
The main() Method
public static void main(String[] args)
• Public : met hod main() dapat diakses oleh apa saj a, t ermasuk j ava
t echnology int erpret er.
• St at ic : keyword ini berf ungsi unt uk memberi t ahu kompiler bahwa
mett hod
h d main
i bisa
bi langsung
l g
g digunakan
dig
k dalam
d l
contt ex class
l
yang
g
bersangkut an. Unt uk mengeksekusi/ menj alankan met hod yang
bert ipe st at ic, t idak diperlukan inst ance nya.
• Void : menunj ukkan bahwa met hod main() t idak mengembalikan nilai
• Main : merupakan nama met hod ut ama dari program j ava
• St ring [ ] args : Menyat akan bahwa met hod main() menerima single
paramet er yait u args yang bert ipe array. Digunakan pada saat memasukkan
paramet er pada saat menj alankan program.
Cont oh: java TestGreeting args[0] args[1] …
JAVA KEYWORDS AND RESERVED WORDS
|
are considered as reserved keywords
|
may not be used as identifiers.
|
None of the reserved words have a capital letters
|
2 keyword that are reserved in Java but which are not used : const dan
goto
abstract do
implements private
this
boolean
double
import
throw
break
else
instanceof public
byte
extends int
return
transient
case
false
interface
short
true
catch
final
long
static
try
char
finally native
strictfp
void
class
float
new
super
volatile
continue for
null
switch
while
default
package
synchronized
if
protected
throws
Public class TestDog{
public static void main(String args[]){
Dog d = new Dog();
d.setWeight(42);
System.out.println(“Dog d’s weight is “ + d.getWeight());
}
}
|
Modifier : public, private, protected, dan default
|
Constructor adalah bukan method, sehingga
gg tidak p
punya
y return values dan
tidak diturunkan/diwariskan
Note:
• Jika kita mendeklarasikan constructor pada suatu
class yang sebelumnya tidak mempunyai constructor,
maka
k d
default
f l constructor class
l
tersebut
b akan
k hilang.
hil
• Sehingga bila constructor yang kita buat tadi
mempunyai
p y argumen,
g
, kemudian kita buat obyek
y
dengan cara new Xxx(), proses kompilasi akan
menghasilkan error.
IDENTIFIERS
|
|
|
|
Nama yang digunakan oleh programer untuk memberi nama
pada variable, class, atau method.
Can start with a Unicode letter, underscore (_), or dollar sign ($)
Are case-sensitive and have no maximum length
Examples:
1.
2.
3.
4.
5
5.
foobar
BIGinterface
$incomeAfterExpenses
3
3_node5
d 5
digit
6. !theCase
7.
//
//
//
//
//
legal
g
legal: embedded keywords
are OK.
legal
ill
illegal:
l starts
t t with
ith a
// illegal: must start with
// letter, $, or _
PRIMITIVE TYPES
|
The Java programming language defines eight
primitive types:
Logical - boolean
b l
y Textual - char
y Integral - byte, short, int, and long
y Floating - double and float
y
PRIMITIVE TYPES
LITERALS
is a value
| cannot appear on the left side of assignments.
|
LOGICAL LITERALS
Th boolean data
The
d t ttype h
has ttwo lit
literals,
l true and
d
false.
| For example,
example the statement:
|
1. boolean isBig = true;
2 boolean
2.
b l
isLittle
i i l = false;
f l
Note: boolean literal tidak boleh berharga 0 atau 1
TEXTUAL LITERALS
The range: 0 ~ 2166 - 1.
| Java characters are in Unicode character (16-bit
encoding).
di )
|
CHAR LITERALS
Expressed by enclosing the desired character in
single quotes (‘ ‘).
| Example:
E
l
char c = ‘w’;
|
Express as a Unicode
E
U i d value
l specified
ifi d using
i four
f
hexadecimal digits, preceded by \u
| Example:
E
l
char c = ‘\u0063’;
|
CHAR LITERALS
|
Special Characters
y
y
y
y
y
y
y
y
‘\n’ for new line
‘\r’
\r for return
‘\t’ for tab
‘\b’ for backspace
p
‘\f’ for formfeed
‘\’’ for single quote
‘\”’ for double quote
‘\\’ for backslash
STRING LITERALS
Is not a primitive data type; it is a class
| Represent sequences of characters
| Has its literal enclosed in double quotes (“ ”)
| Example:
|
String s = “Characters in strings are 16-bit
Unicode.”;
String s = “Good Morning !! \n”;
INTEGRAL LITERALS Æ BYTE, SHORT, INT
AND LONG
|
E
Expressed
d in
i decimal,
d i l octal,
t l or hexadecimal.
h
d i l
2
The decimal value is 2
077
The leading 0 indicates an octal value
0xBAAC The leading 0x indicates a
hexadecimal value
|
Specify a long integer by putting an 'L' or 'l' after
the number.
'L' is preferred as it cannot be confused with the digit '1'.
y Example:
y
long
g x = 25L;
;
|
Has a default type of int
INTEGRAL
FLOATING-POINT LITERALS
|
Floating
Fl
ti point
i t literal
lit
l includes
i l d either
ith a decimal
d i l
point or one of the following:
y
y
y
E or e (add exponential value)
F or f (float)
D or d (double)
3.14
Æ a simple
p floating
gp
point value ((a double))
6.02E23
Æ a large floating point value
2.718F
Æ a simple float size value
123.4E306D Æ a large double value
Default is double
| Specify a float by putting an ‘F' or ‘f' after the
number.
b
|
y
Example:
float x = 2.5F;
NOTE:
Semua tipe data primitif yang numerik (selain char
dan boolean) adalah signed.
MEMBER VARIABLES INITIALIZATION
Reference variable
ARGUMENT PASSING
The Java programming language only passes
arguments by value
| When
Wh an object
bj t instance
i t
is
i passed
d as an
argument to a method, the value of the argument
is a reference to the object
| The contents of the object can be changed in the
called method, but the object reference is never
changed
|
> java PassTest
I nt value is: 11
y
22-7-1964
MyDate:
MyDate: 4-7-1964
GARBAGE COLLECTION
|
|
|
|
Allocated
All
t d memory that
th t is
i no longer
l
needed
d d should
h ld b
be
deallocated
In other languages, deallocation is the programmer's
responsibility
The Java programming language provides a system-level
y allocation
thread to track memory
Garbage collection:
Checks for and frees memory no longer needed
y Is done automatically
y Can vary dramatically across JVM implementations
y
|
“run the garbage collector.”
y
System.gc() and Runtime.gc()
http:/ / java.sun.com/ javaee/ 5/ docs/ api/
http:/ / java.sun.com/ j2se/ 1.5.0/ docs/ api/
PROGRAMMING
D
Day
2:
Dasar Pemrograman Java
TOPIK:
|
|
|
|
|
|
|
|
|
|
|
Menggunakan
M
k komentar
k
t di file
fil sumber.
b
Membedakan antara valid dan invalid identifiers.
Mengetahui
g
Java technology
gy keywords.
y
Mengetahui 8 tipe data primitif.
Mendefinisikan literal value untuk tipe data numerik dan
tekstual.
tekstual
Mendefinisikan primitive dan reference variable.
Mendeklarasikan variabel bertipe
p class.
Membuat obyek dengan menggunakan operator new.
Mengetahui nilai inisialisasi default.
St t t t pada
State-state
d saatt assign
i nilai
il i pada
d variabel
i b l bertipe
b ti
class
Garbage collection
SOURCE FILES
|
|
Java source fil
J
files must end
d with
i h the
h .java
extension.
Th
Three
top-level
t l
l elements
l
t known
k
as compilation
il ti
units may appear in a file.
Package Declaration
y Import Statements
y Class Definitions
y
CLASS FUNDAMENTALS: MAIN METHOD
|
The main() Method
public static void main(String[] args)
• Public : met hod main() dapat diakses oleh apa saj a, t ermasuk j ava
t echnology int erpret er.
• St at ic : keyword ini berf ungsi unt uk memberi t ahu kompiler bahwa
mett hod
h d main
i bisa
bi langsung
l g
g digunakan
dig
k dalam
d l
contt ex class
l
yang
g
bersangkut an. Unt uk mengeksekusi/ menj alankan met hod yang
bert ipe st at ic, t idak diperlukan inst ance nya.
• Void : menunj ukkan bahwa met hod main() t idak mengembalikan nilai
• Main : merupakan nama met hod ut ama dari program j ava
• St ring [ ] args : Menyat akan bahwa met hod main() menerima single
paramet er yait u args yang bert ipe array. Digunakan pada saat memasukkan
paramet er pada saat menj alankan program.
Cont oh: java TestGreeting args[0] args[1] …
JAVA KEYWORDS AND RESERVED WORDS
|
are considered as reserved keywords
|
may not be used as identifiers.
|
None of the reserved words have a capital letters
|
2 keyword that are reserved in Java but which are not used : const dan
goto
abstract do
implements private
this
boolean
double
import
throw
break
else
instanceof public
byte
extends int
return
transient
case
false
interface
short
true
catch
final
long
static
try
char
finally native
strictfp
void
class
float
new
super
volatile
continue for
null
switch
while
default
package
synchronized
if
protected
throws
Public class TestDog{
public static void main(String args[]){
Dog d = new Dog();
d.setWeight(42);
System.out.println(“Dog d’s weight is “ + d.getWeight());
}
}
|
Modifier : public, private, protected, dan default
|
Constructor adalah bukan method, sehingga
gg tidak p
punya
y return values dan
tidak diturunkan/diwariskan
Note:
• Jika kita mendeklarasikan constructor pada suatu
class yang sebelumnya tidak mempunyai constructor,
maka
k d
default
f l constructor class
l
tersebut
b akan
k hilang.
hil
• Sehingga bila constructor yang kita buat tadi
mempunyai
p y argumen,
g
, kemudian kita buat obyek
y
dengan cara new Xxx(), proses kompilasi akan
menghasilkan error.
IDENTIFIERS
|
|
|
|
Nama yang digunakan oleh programer untuk memberi nama
pada variable, class, atau method.
Can start with a Unicode letter, underscore (_), or dollar sign ($)
Are case-sensitive and have no maximum length
Examples:
1.
2.
3.
4.
5
5.
foobar
BIGinterface
$incomeAfterExpenses
3
3_node5
d 5
digit
6. !theCase
7.
//
//
//
//
//
legal
g
legal: embedded keywords
are OK.
legal
ill
illegal:
l starts
t t with
ith a
// illegal: must start with
// letter, $, or _
PRIMITIVE TYPES
|
The Java programming language defines eight
primitive types:
Logical - boolean
b l
y Textual - char
y Integral - byte, short, int, and long
y Floating - double and float
y
PRIMITIVE TYPES
LITERALS
is a value
| cannot appear on the left side of assignments.
|
LOGICAL LITERALS
Th boolean data
The
d t ttype h
has ttwo lit
literals,
l true and
d
false.
| For example,
example the statement:
|
1. boolean isBig = true;
2 boolean
2.
b l
isLittle
i i l = false;
f l
Note: boolean literal tidak boleh berharga 0 atau 1
TEXTUAL LITERALS
The range: 0 ~ 2166 - 1.
| Java characters are in Unicode character (16-bit
encoding).
di )
|
CHAR LITERALS
Expressed by enclosing the desired character in
single quotes (‘ ‘).
| Example:
E
l
char c = ‘w’;
|
Express as a Unicode
E
U i d value
l specified
ifi d using
i four
f
hexadecimal digits, preceded by \u
| Example:
E
l
char c = ‘\u0063’;
|
CHAR LITERALS
|
Special Characters
y
y
y
y
y
y
y
y
‘\n’ for new line
‘\r’
\r for return
‘\t’ for tab
‘\b’ for backspace
p
‘\f’ for formfeed
‘\’’ for single quote
‘\”’ for double quote
‘\\’ for backslash
STRING LITERALS
Is not a primitive data type; it is a class
| Represent sequences of characters
| Has its literal enclosed in double quotes (“ ”)
| Example:
|
String s = “Characters in strings are 16-bit
Unicode.”;
String s = “Good Morning !! \n”;
INTEGRAL LITERALS Æ BYTE, SHORT, INT
AND LONG
|
E
Expressed
d in
i decimal,
d i l octal,
t l or hexadecimal.
h
d i l
2
The decimal value is 2
077
The leading 0 indicates an octal value
0xBAAC The leading 0x indicates a
hexadecimal value
|
Specify a long integer by putting an 'L' or 'l' after
the number.
'L' is preferred as it cannot be confused with the digit '1'.
y Example:
y
long
g x = 25L;
;
|
Has a default type of int
INTEGRAL
FLOATING-POINT LITERALS
|
Floating
Fl
ti point
i t literal
lit
l includes
i l d either
ith a decimal
d i l
point or one of the following:
y
y
y
E or e (add exponential value)
F or f (float)
D or d (double)
3.14
Æ a simple
p floating
gp
point value ((a double))
6.02E23
Æ a large floating point value
2.718F
Æ a simple float size value
123.4E306D Æ a large double value
Default is double
| Specify a float by putting an ‘F' or ‘f' after the
number.
b
|
y
Example:
float x = 2.5F;
NOTE:
Semua tipe data primitif yang numerik (selain char
dan boolean) adalah signed.
MEMBER VARIABLES INITIALIZATION
Reference variable
ARGUMENT PASSING
The Java programming language only passes
arguments by value
| When
Wh an object
bj t instance
i t
is
i passed
d as an
argument to a method, the value of the argument
is a reference to the object
| The contents of the object can be changed in the
called method, but the object reference is never
changed
|
> java PassTest
I nt value is: 11
y
22-7-1964
MyDate:
MyDate: 4-7-1964
GARBAGE COLLECTION
|
|
|
|
Allocated
All
t d memory that
th t is
i no longer
l
needed
d d should
h ld b
be
deallocated
In other languages, deallocation is the programmer's
responsibility
The Java programming language provides a system-level
y allocation
thread to track memory
Garbage collection:
Checks for and frees memory no longer needed
y Is done automatically
y Can vary dramatically across JVM implementations
y
|
“run the garbage collector.”
y
System.gc() and Runtime.gc()
http:/ / java.sun.com/ javaee/ 5/ docs/ api/
http:/ / java.sun.com/ j2se/ 1.5.0/ docs/ api/